SRI International's CubeSat Identification Tag (CUBIT): System Architecture and Test Results from Two On-Orbit Demonstrations

SRI International (SRI) developed the CubeSat Identification Tag (CUBIT) radio frequency (RF) transponder to demonstrate a low-SWaP (size, weight, and power) CubeSat RF-based identification system. CUBIT addresses the growing need to identify CubeSats post deployment as mass launches become more commonplace. Such launches make it difficult to assess which radar return belongs to which CubeSat, especially with the high mortality rates seen within the CubeSat community. Conversations with developers highlighted the need for better satellite identification for improved troubleshooting. Even for functioning CubeSats, the lack of accurate two-line elements (TLEs) increased the likelihood that ground assets were improperly aimed at the correct satellite. CUBIT seeks to address this need through a low-cost RF transponder. This paper outlines the CUBIT system architecture. SRI’s tag concept is composed of: (1) an internal Electronics Unit (EU) containing batteries, radio, and microprocessor and (2) an Antenna Unit (AU) containing the antenna and an inhibit photocell mounted on the CubeSat exterior. SRI successfully demonstrated the CUBIT system during two On-Orbit operations. SRI teamed with NASA Ames for CUBIT’s first demonstration using a collocated beacon and time domain signal analysis to confirm operation. In the second demonstration, CUBIT identified a passive CubeSat during a clustered launch and confirmed its deployment when other means provided ambiguous results.